Susan Solomon, ozone hole luminary and Nobel Prize winning chair of IPCC, and her colleagues, have just published a paper entitled “Irreversible climate change because of carbon dioxide emissions” in the Proceedings of the National Academy of Sciences. We at realclimate have been getting a lot of calls from journalists about this paper, and some of them seem to have gone all doomsday on us. Dennis Avery and Fred Singer used the word Unstoppable as a battle flag a few years ago, over the argument that the observed warming is natural and therefore there is nothing that humanity can do to alter its course. So in terms of its intended rhetorical association, Unstoppable = Burn Baby Burn. But let’s not confuse Irreversible with Unstoppable. One means no turning back, while the other means no slowing down. They are very different words. Despair not!
Technical Note: We have changed the contact email for the blog to reduce the amount of unsolicited email. If you want to contact us at the blog, please use contact-at-realclimate.org.
In the New York Review of Books, Freeman Dyson reviews two recent ones about global warming, but his review is mostly shaped by his own rather selective vision.
1. Carbon emissions are not a problem because in a few years genetic engineers will develop “carbon-eating trees” that will sequester carbon in soils. Ah, the famed Dyson vision thing, this is what we came for. The seasonal cycle in atmospheric CO2 shows that the lifetime of a CO2 molecule in the air before it is exchanged with another in the land biosphere is about 12 years. Therefore if the trees could simply be persuaded to drop diamonds instead of leaves, repairing the damage to the atmosphere could be fast, I suppose. The problem here, unrecognized by Dyson, is that the business-as-usual he’s defending would release almost as much carbon to the air by the end of the century as the entire reservoir of carbon stored on land, in living things and in soils combined. The land carbon reservoir would have to double in size in order keep up with us. This is too visionary for me to bet the farm on.
The physical impacts of the global warming forecast can be bracketed with some degree of statistical confidence. Biological effects are more difficult to gauge, except in special cases such as the likely demise of polar bears that would result from the demise of Arctic sea ice. The societal effects, however, are nearly uncharted territory, at least to me. Perhaps the topic of global warming suffers from the same sort of cultural divide as university faculties, between the techies and the touchies; that is the sciences and the humanities. A new report (pdf) called The Age of Consequences, just released by the Center for Strategic and International Studies and the Center for a New American Security, tries to bring the social sciences, in particular history, geography, and political science, into the forecast of climate change in the coming century. It makes for fascinating if frightening reading. More »
The summer of 2007 was apocalyptic for Arctic sea ice. The coverage and thickness of sea ice in the Arctic has been declining steadily over the past few decades, but this year the ice lost an area about the size of Texas, reaching its minimum on about the 16th of September. Arctic sea ice seems to me the best and more imminent example of a tipping point in the climate system. A series of talks aimed to explain the reason for the meltdown. More »
Just a few minutes ago Chappellaz et al presented the deepest dregs of greenhouse gas concentration data from the EPICA ice core in Antarctica, extending the data back to 800,000 years ago. In Al Gore’s movie you saw what was at that time the longest record of atmospheric greenhouse gas concentrations, back to 650 kyr, and their astonishing correlation with Antarctic temperature. This iconic superstar record has probably consumed as many eyeball-hours as any in climate science, alongside other classics such as the Jones et al. global temperature trends, the Moana Loa recent CO2 record, and the hockey stick. The Antarctic CO2 record has spawned countless internet rants about the CO2 lag behind temperature, and the circle of cause and effect between CO2 and climate. And the new data say … More »